A Monmouth County man was sentenced to 20 years in prison Thursday after pleading guilty to a string of threatening communications to state officials, law enforcement, attorneys and other public offices around the state, U.S. Attorney Philip R. Sellinger announced Thursday. Eric G. Hafner, 32, was sentenced Thursday in federal court in Trenton after pleading guilty on May 17, 2022 to making threatening statements and one count of conveying false information regarding the use of an explosive device. Hafner’s threats were made by both phone and email. “This defendant repeatedly targeted public s…